/Engine/Source/Runtime/Engine/Classes/Components/PrimitiveComponent.h
Set the linear velocity of a single body. This should be used cautiously - it may be better to use AddForce or AddImpulse.
virtual void SetPhysicsLinearVelocity ( FVector NewVel, bool bAddToCurrent, [FName](API\Runtime\Core\UObject\FName) BoneName )